A264719 - OEIS

%I #11 Nov 25 2015 20:52:38

%S 10,11,16,17,22,27,28,29,35,36,37,40,41,46,51,52,57,58,59,65,66,67,70,

%T 71,77,78,79,82,87,88,94,95,96,97,100,101,106,107,112,121,122,123,124,

%U 125,126,127,130,135,136,137,145,146,147,148,149,155,156,161,162

%N Numbers that are greater than the average of their closest flanking primes.

%C Numbers that are nearer to the immediately next prime than to the immediately previous prime.

%C This sequence may be viewed as a generalization of A051634 (the strong primes) that includes qualifying composite numbers.

%C The union of this sequence with A264720 & A145025 is A000027 (omitting 1 & 2).

%H Chris Boyd, <a href="/A264719/b264719.txt">Table of n, a(n) for n = 1..10000</a>

%e a(11) = 37 because 37 > (31 + 41)/2 = 36.

%e a(12) = 40 because 40 > (37 + 41)/2 = 37.

%t Select[Range@ 162, # > (Abs@ NextPrime[#, -1] + NextPrime@ #)/2 &] (* _Michael De Vlieger_, Nov 22 2015 *)

%o (PARI) test(n)= {if(n-precprime(n-1)>nextprime(n+1)-n&&n>2,return(1),return(0))}

%o for(i=1,200,if(test(i),print1(i,", ")))

%Y Cf. A051634, A145025, A264720, A264721, A264722.

%K nonn,easy

%O 1,1

%A _Chris Boyd_, Nov 21 2015